Drove to Canada from New York and landed in Toronto as a new immigrant this week. Applied for H1B visa stamp as a Canadian permenant resident at the US Consulate in Toronto the next day. I asked the visa officer if he could grant me multiple entries for 3 years considering my Canadian permenant resident status. Luckily, he said "this is what I am going to do for your case."
Today I went back to the consulate to pick up my passport, on which there is a new H1B visa stamp with unlimited entries valid until my H1B expiration date.
Seems it's one of the Canadian PR benefits. : )
In the past, I applied for H1B visa stamp in both Mexico and Canada and each time I got only 2 entries/3 months as a Chinese citizen.